The combination of polymers and inorganic filler materials is known for the production of nanocomposite materials with improved mechanical, thermal and barrier properties as compared to the unmodified polymer. A detailed discussion of nanocomposites can be found in Ajayan, P. M., Nanocomposite Science and Technology (Wiley, 2003).
The combination of polymers with layered silicates, also known as smectite clays or phyllosilicates, has been exploited as a means for the synthesis of nanocomposites. Comprehensive reviews on the subject are Alexandre and Dubois (2001) and Pinnavaia, T. J.; Beall, G. W. Polymer Clay Nanocomposites Wiley New York, 2000. Smectite clays are described in Grim, R. E. Clay Mineralology 2nd edition; McGraw-Hill: New York 1968.
Several methods for the synthesis of polymer clay nanocomposites have been described in the art, for example Nylon/clay composites first described by Usuki et al. (1993). A. Usuki, et al., “Synthesis of nylon 6-clay hybrid”, J. Mater. Res., vol. 8, No. 5, May 1993, pp. 1179-1184. In this process nylon and montmorillonite are combined at high temperature to give an exfoliated nanocomposite with improved material properties relative to the polymer alone.
A biodegradable thermoplastic material comprising a natural polymer, a plasticizer and an exfoliated clay having a layered structure and a cation exchange capacity of from 30-350 milliequivalents per 100 grams is described in U.S. Pat. No. 6,811,599 B2. The natural polymer is a polysaccharide.
A smectite clay modified with an organic chemical composition and a polymer is described in U.S. Pat. No. 6,521,690.
Nanocomposites formed from phyllosilicates and the synthetic homopolymer poly-L-lysine have been described. (Krikorian, V. et al. J. Polym. Sci. B: Polym. Phys. 2002, 40, 2579). Soy protein isolate has also been incorporated into nanocomposites containing sodium montmorillonite clay (Chen, P. and Zhang, L. Biomacromolecules, 2006, 7, 1700).
Proteins make up the main structural elements of most organisms, using complex sequences of amino acids that lead to wide arrays of functionalities. One of the most intensely studied structural proteins, Bombyx mori silkworm silk, has generated significant interest because of its remarkable mechanical properties, which rival even spider silk. Elastin, another well-known structural protein, is found predominantly in the body's arterial walls, the lungs, intestines, and skin. Silk elastin like protein (SELP) is a recombinant protein consisting of alternating blocks of silk-like and elastin-like amino acids. The mechanical properties of recombinant proteins like SELP are often inferior to structural proteins found in nature.
The use of recombinant proteins in in-vivo applications and in applications outside of the body may demand improvements and alterations in a wide variety of properties, including high temperature mechanical behavior.